1. Field of the Invention
This invention relates to photographic film and to a method for rapid access processing of continuous web form or web carried instant of self-developing photographic films.
2. Description of the Prior Art
The term "rapid access", as used herein and in the appended claims, is intended to delineate a type of photographic film or film processing which is capable of providing an image on a substrate which has been exposed directly to light defining the image or to which an image is transferred from another image or image facsimile bearing media, by application of a processing liquid layer over the area of the image to be provided. The most common form of rapid access film processing is the diffusion transfer process used in the field of instant photography, and in which a processing liquid is spread over the surface of a sheet or web carried exposed photosensitive emulsion so that the unexposed grains of silver halide in the emulsion layer are transferred to a positive image-receiving layer or layer interface. The process has been used extensively for many years to provide positive photographic prints in which the transfer of unexposed grains from the emulsion layer on a negative sheet, for example, is to image-receiving layer either on a separate positive sheet or incorporated in a photochemical system contained between coextensive opaque and transparent sheets. More recently, positive image transparencies have been developed in which both the photosensitive emulsion layer and the image-receiving layer are carried on a single transparent web or sheet so that upon processing, the transfer occurs between the emulsion layer and the image-receiving layer. Other types of films are known, however, where exposed and unexposed grains or dyes in an emulsions are processed to provide an image without transfer.
Commonly assigned U.S. Pat. No. 4,519,689 discloses a method and apparatus for rapid access processing directed particularly to film systems in which only the final photographic product is delivered as a discrete sheet separated during the latter stages of processing from a carrier web on which it was supported for processing. All other spent components of the film system, such as spent processing liquid pods, the exposed and processed negative, as well as any residual processing liquid remaining about the edges of the final product, were left remaining on the carrier web wound onto a roll to be discarded. As a result, the finished sheet products were ejected from the processor in a clean and easily handled condition.
While the delivery of discrete photographic sheets by processing systems of the type disclosed in the aforementioed U.S. patent is preferred for many applications, in other applications, such as where it is desired to preserve the photographs in a particular sequence or order or to preserve grouping of the photographs at least for some determinate period of time after processing, it is preferred that the photographic products be delivered form the processor as sheets mounted on a carrier web or as separate image frames on a continuous web of positive photographic sheet material, for example. In this situation, a problem occurs as a result of processing liquid being spread beyond the side and trailing edges of either the carrier mounted sheet or of the image frame in a continuous single web. Such residual processing liquid is not only a source of contamination of the photographic product delivered form the processor, but is generally undesirable to the person who must handle the processed product to separate the finished photographs from the continuous carrier web either by peeling separation or by cutting. There is need, therefore, for a rapid accessing process and apparatus by which the product of same may be delivered in continuous form and free of processing liquid.